At present, about one quarter of a billion tires are being discarded every year in the United States. It is estimated that two to six billion scrap tires are currently stockpiled. Landfill disposal of tires is impractical due to handling problems and the landfill space the tires consume. While federal and state agencies have focused on this problem, efforts to find a better solution to tire disposal or to recycle the tires have been unsuccessful.
Environmental regulations concerning the disposal of used automobile and truck tires are rapidly being legislated state by state in an effort to eliminate the landfill disposal of the tires. Most of the regulations include programs promoting the development of practical commercial products made from used tires. The success of recycling is based on the successful development of markets and uses for the recycled materials. It is, therefore, environmentally desirable and necessary to find a beneficial use for the used tires.
In the field of geotechnical engineering, there is an increasing need to impose manmade solutions on earth related projects to reinforce, improve, protect or beautify the earth. Shoreline protection against erosion is a typical example of the need for manmade protection of an earth structure. An unprotected shoreline can erode away due to current action, wave action or surface water runoff. As a shoreline erodes, valuable land is lost. Structures such as stream, lake or canal banks; slopes; dams; levees and jetties are often threatened or damaged. Movement of the eroded soil into the water is a form of water pollution.
Traditional solutions to shoreline protection, for example, retaining walls, seawalls, shoring, bulkheads, jetties, groins and revetment systems, are very expensive and limited in their use. Also, these systems do not include a light weight but strong flexible system which can be anchored to a slope.
The present invention offers a cost effective geotechnical engineering material which helps solve a waste tire disposal problem and offers a significant environmental contribution.
Therefore, the broad object of this invention is a high strength geotechnical engineering material constructed from the tread portion of tires and used for erosion control and soil stabilization and reinforcement.
A prior attempt to use whole tire casings along shorelines for erosion control is taught in and by U. S. Pat. No. 4,080,793. The system utilized whole tire casings to form an open system which is generally used in combination with a soil, aggregate or concrete fill to anchor the system. Such systems generally rely on the fill material within tire casings to be part of the final face of the erosion control system either with or without vegetation establishment in the fill material. Vegetation and fill are also used to help conceal the whole tire casings which are visually offensive. Early attempts of merely dumping whole tire casings for slope protection and erosion control were unsightly and environmentally unfriendly systems due to water retention and mosquito breeding in the tire casings. Another engineering use of waste tires is as shredded tire pieces used as fill in asphalt concrete or as road base material. However, by shredding the tire, the inherent strength of the reinforced tread portion of the tire is lost.